A motor vehicle typically houses a heat engine in an engine compartment, usually forward of a cab or body containing the occupant compartment. Engine compartment temperatures are a matter of concern to vehicle designers because excessively high temperatures can have adverse effects on the performance and durability of various devices and systems.
Space within an engine compartment is often at a premium for vehicle designers. As an engine compartment becomes increasingly crowded, more components are exposed to engine compartment heat, and the more difficult it becomes to move air that can aid in limiting temperatures through the engine compartment.
Control of engine operating temperature can to some extent control temperatures in various locations in the engine compartment, but engine operating temperature may itself be affected by various considerations that impose a lower limit on operating temperature. For example, higher operating temperature may be necessary in order to enable compliance with relevant emission control regulations, and while the cooling system of a liquid cooled engine can be sized to allow an engine to have a higher operating temperature, more engine heat will be transferred by convention, conduction, and/or radiation to devices in the engine compartment, to the structure bounding the engine compartment, and to air in the engine compartment because those forms of heat transfer do not occur through the liquid cooling system.
Furthermore, radiator placement in certain vehicles causes at least some of the heat that is rejected to air flowing through the radiator to pass back through the engine compartment. Higher engine temperatures and reductions in air flow through an engine compartment can create hot spots, or hot zones, potentially affecting devices located in the immediate vicinity.
Consequently, certain vehicles may benefit from a heat removal system and method devoted to improving heat removal from such hot spots, or hot zones.
Another area where excessive heat may be generated involves service brakes at a vehicle's wheels for decelerating the vehicle when a brake pedal is depressed. The brakes are typically friction brakes that when operated, slow the vehicle by frictional force that converts kinetic energy into heat. A drum-type brake has brake shoes that are disposed within a confined space. Because significant heat can be generated in that space, it too may benefit from a heat removal system and method devoted to improving heat removal.